Generally spherical barium carbonate particles, and method for producing generally spherical barium carbonate particles

a technology of barium carbonate and spherical barium carbonate, which is applied in the direction of barium carbonate, natural mineral layered products, cellulosic plastic layered products, etc., can solve the problems of reducing the surface energy of particles, affecting the quality of barium carbonate,

Active Publication Date: 2012-02-23
SAKAI CHEM IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0013]Indeed, the methods described in Patent Documents 1 or 2 can easily achieve a specific surface area of the particles to be higher than 10 m2 / g with a help of carboxylic acids or pyrophosphoric acid. However, the particles are in a spicular shape. In particular, when citric acid is added, particles can grow to be more spicular. Thus, it has been difficult by the methods described in Patent Document 1 or 2 to produce desired highly pure, spherical fine particles.
[0017]Under these circumstances, the present inventors have found that specific compounds belonging to gluconic acid or its derivatives are effective to produce a spherical particles of barium carbonate, and have completed an invention relating to a method of producing uniform, substantially spherical (preferably, spherical) particles only by a synthetic step. The inventors have also found that, by the method, uniform spherical particles that contain substantially no impurities can be efficiently produced.

Problems solved by technology

However, when barium carbonate fine particles are dispersed in water, particles tend to aggregate to decrease the surface energy of particles.
However, sufficient strength of grinding is required and it takes long time to produce fine particles with a low aspect ratio.

Method used

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  • Generally spherical barium carbonate particles, and method for producing generally spherical barium carbonate particles
  • Generally spherical barium carbonate particles, and method for producing generally spherical barium carbonate particles
  • Generally spherical barium carbonate particles, and method for producing generally spherical barium carbonate particles

Examples

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example 1

[0099]Barium hydroxide octahydrate was dissolved in pure water to prepare a solution. To four separate flasks containing the solution, 50% gluconic acid solution (produced by FUSO Chemical Co., Ltd.) was added such that the concentration of gluconic acid should be 10, 30, 50, or 70 mol %, respectively, based on the mole of barium ion in barium hydroxide . Then, the solutions were diluted with pure water such that the final concentration of the solution should be 120 g / L based on the barium hydroxide octahydrate, to prepare an aqueous barium hydroxide-gluconic acid solution (referred to as “Raw material A”) was prepared. The temperature of the solution at that time was adjusted to 50° C. In the reaction apparatus schematically illustrated in FIG. 1, the raw material A was fed into the reaction vessel at a flow rate of 300 ml / min. Simultaneously, gaseous CO2 was fed into the reaction vessel at a flow rate of 9 L / min, and then the reaction mixture was stirred at high speed with IKA hom...

example 2

[0104]Barium carbonate was produced in a larger scale with reference to the results of Example 1. Reaction apparatus used in this Example 2 included sequentially-connected, three pumps P1, P2 and P3, as illustrated in FIG. 15. The pumps used are the followings. Here, 1 inch (in)=about 2.54 cm.

(a) First phase pump P1: a centrifugal pump (manufactured by RASA CORPORATION), inlet diameter: 1.5 in, outlet diameter: 1 in, discharging rate : 170 L / min, impeller revolution: 2,080 rpm

(b) Second phase pump P2: a centrifugal pump (manufactured by RASA CORPORATION), inlet diameter: 1 in, outlet diameter: ¾ in, discharging rate: 30 L / min, impeller revolution: 1,420 rpm

(c) Third phase pump P3: a centrifugal pump (manufactured by PACIFIC METALS Co., Ltd.), inlet diameter: 1 in, outlet diameter: ¾ in, discharging rate: 30 L / min, impeller revolution: 1,420 rpm

[0105]Barium hydroxide octahydrate (48 kg) was dissolved in pure water, and then gluconic acid was added in an amount corresponding to 50 mol...

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Abstract

The present invention has an object to provide a method for producing particulate barium carbonate having desired properties such as high purity, fineness, and has a spherical shape. The present invention relates to a method of producing substantially spherical barium carbonate, including (A) mixing, in an aqueous medium, a barium compound with at least one first ingredient selected from the group consisting of gluconic acid or salts thereof, gluconolactone, glucoheptonic acid or salts thereof, and glucoheptonolactone, to prepare a mixture; and (B) reacting the barium compound with carbon dioxide or a water-soluble carbonate in the mixture, to produce substantially spherical barium carbonate.

Description

TECHNICAL FIELD[0001]The present invention relates to substantially spherical barium carbonate which is suitable mainly for a material for electronic parts or for phosphors, a method for substantially spherical fine barium carbonate, and a composition containing substantially spherical barium carbonate.BACKGROUND OF THE INVENTION[0002]Barium carbonate is one of main raw materials of barium titanate, which is used for electronic materials. Recent development for downsizing and upgrade of electronic devices requires improvement of the capacity and performance of monolithic ceramic chip capacitors. For such improvement, barium titanate, which is a raw material of monolithic ceramic chip capacitors, has been required to have higher purity and finer size.[0003]Barium titanate is generally produced by mixing barium carbonate and titanium dioxide in a wet form, and drying, followed by calcination. To produce high quality barium titanate, it is desired to perform uniform wet mixing and unif...

Claims

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Application Information

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IPC IPC(8): C01F11/18B32B5/16
CPCC01F11/188C01P2004/03C01P2004/32Y10T428/2982C01P2004/54C01P2006/12C09C1/02C01P2004/34C01F1/00C01F11/18
Inventor SHIMIZU, YUSUKEIZUMIKAWA, HIROYUKI
Owner SAKAI CHEM IND CO LTD
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